Personal identification is a critical process in the forensic sciences. Law enforcement agents and forensic laboratories around the world use fingerprint, palmprint, facial recognition, deoxyribonucleic acid (DNA), and teeth regularly for criminal and victim identification. However, these biometric traits are not applicable to the legal cases when only evidence images are available. Recent technological advances have allowed for a proliferation of digital evidence images, which may be admissible as evidence in legal cases (e.g. child sexual abuse, child pornography and masked gunmen/terrorists). However, use of these images can be very challenging, because the faces of criminals or victims are more than often not visible.
For example, the United States Bureau of Justice Statistics has reported that child sex offenses are the fastest growing offenses of the Federal criminal caseload. Many individuals post child pornography on the Internet and anyone who possesses, makes, prints, publishes, distributes, sells or imports child pornography commits a criminal offense. Criminals are usually careful not to show their faces in child pornography for fear of identification. Due to the lack of effective identification technology, a huge amount of child pornography has been posted on the Internet. For example, in Canada alone, about 30,000 cases of child pornography have been reported. The U.S. Customs Service has estimated that about 100,000 websites offer child pornography. In addition to child pornography, personal identification based on evidence images or videos may be applicable to many other crimes such as rape, sexual assault, and masked gunmen.
Even though tattoos and large skin marks have been used, they are ineffective in some of these cases because the skin exposed in evidence images may have neither unique tattoos nor enough skin marks for personal identification. For example, some people, especially gang members, can have the same tattoo pattern, while many may not have tattoos. A similar problem may be faced when dealing with skin marks.
Vein recognition is a biometric technology that performs personal verification and identification based on the vast network of blood vessels under the skin surface. The blood vessel between the skin and the muscle covering most parts of the human body is a powerful biometric trait, because of its universality, permanence and distinctiveness. It is considered to be a unique and stable biometric trait that is nearly impossible to forge. The vast network of larger blood vessels is believed to be “hardwired” into the body at birth, and remains relatively unaffected by aging, except for predictable growth, as with fingerprints. In addition, as the blood vessels are hidden underneath the skin and are almost invisible, they are much harder to be duplicated compared with other biometric traits.
Vein biometrics has received considerable attention in the last decade for commercial applications. The current systems developed in laboratories and companies use infrared (IR) or laser imaging technologies to obtain high quality vein patterns from the hand (e.g. finger and palm) and the wrist for commercial applications. However, these approaches are inapplicable to forensic identification from colour images, where no infrared or laser images are available and vein patterns are not visible in these colour images.
Uncovering vein patterns from digital or colour images taken by consumer cameras is challenging because the veins lie underneath the skin surface and are almost invisible to the naked eye. Skin is an intricate layered material whose internal structures vary with individuals, body sites, and time. Additionally, the physical process of image formation may complicate the uncovering of vein patterns from the colour images. When the light from an illumination source hits the skin, some is absorbed while some is reflected and captured by the sensor in a camera. Currently there has been no report of any algorithm or software package especially designed for uncovering vein patterns from colour images taken by consumer cameras.
Thus, there is a need to provide a method and an apparatus seeking to address at least the problems mentioned such that vein patterns from the skin in colour images are uncovered for personal identification.